Unit sizing by bankroll
A 'unit' is your standard bet size. Most professional bettors size at 1% of bankroll per typical bet, with a 2-3% allowance for higher-conviction plays.
| Bankroll | 0.5% (cautious) | 1% (standard) | 2% (high conviction) | 3% (max) | 5% (red flag) |
|---|---|---|---|---|---|
| $500 | $2 | $5 | $10 | $15 | $25 |
| $1,000 | $5 | $10 | $20 | $30 | $50 |
| $2,500 | $12 | $25 | $50 | $75 | $125 |
| $5,000 | $25 | $50 | $100 | $150 | $250 |
| $10,000 | $50 | $100 | $200 | $300 | $500 |
| $25,000 | $125 | $250 | $500 | $750 | $1250 |
5% of bankroll per bet is excessive for any sustained strategy. Avoid.
Stop-loss rules
- Daily stop: 5-7% of bankroll. Lose this much in a day, walk away.
- Weekly stop: 12-15% of bankroll. Re-evaluate strategy.
- Monthly stop: 25% of bankroll. Take a hard look at process.
- Tilt rule: after two consecutive losses, halve your unit size for the next 5 bets.
Drawdown survival
Even +EV strategies experience long losing streaks. Plan for them.
| Win rate (-110) | Probability of 5-bet losing streak | 10-bet streak | 15-bet streak |
|---|---|---|---|
| 52.4% (break-even) | 2.4% | 0.06% | 0.001% |
| 54% | 2.0% | 0.04% | 0.0008% |
| 56% | 1.6% | 0.02% | 0.0004% |
Single-streak probabilities. Across a 500-bet season, you'll see at least one 5-loss streak with very high probability — this is variance, not edge failure.
Kelly Criterion shortcut
Full Kelly is mathematically optimal for compounding but emotionally brutal because of the variance. Most pros use fractional Kelly (¼ to ½). Quick rule:
- Edge of 1-2%: bet 0.5% of bankroll.
- Edge of 3-5%: bet 1% of bankroll.
- Edge of 5-8%: bet 1.5-2% of bankroll.
- Edge of 8%+: bet 2-3% — but check your model carefully; double-digit edges are rare and usually wrong.
For exact sizing: Kelly calculator.
The four rules
- Never bet money you can't afford to lose.
- Cap unit size at 2-3% of bankroll.
- Track every bet. Track CLV.
- Never chase. The math hates you for it.